The present invention relates to a rear vehicle-body structure which comprises a damper support portion to support a rear suspension damper and a frame member extending in a vehicle longitudinal direction, such as a rear side frame, wherein the frame member is configured to serve as the damper support portion.
As exemplified by Japanese Patent Laid-Open Publication No. 2003-137140, a rear vehicle-body structure in which a damper support portion (a suspension attachment portion (33)) to support a rear suspension damper (hereafter, referred to as a “damper”) is provided at a position located on an outward side, in a vehicle width direction, of a frame member (a rear side frame (7)) and on an inward side, in the vehicle width direction, of a wheel house inner (19) is known.
Herein, differently from the above-described structure of the patent document where the frame member, the damper support portion, and the wheel house inner are arranged along the vehicle width direction, it may be considered that a recessed portion 150 is formed at a frame member 160, wherein the recessed portion 150 is configured such that a lower face of the frame member 160 is recessed upwardly, and a damper (not illustrated) is inserted, from below, into and supported at a damper insertion hole 151 which is formed at a recessed bottom of the recessed portion 150, similarly to a rear vehicle-body structure 100 illustrated in FIG. 11 and FIG. 12 which shows a sectional view taken along line D-D of FIG. 11.
By providing the recessed portion to support the damper at the frame member as described above, the frame member is provided to be offset inwardly, in the vehicle width direction, compared to a conventional frame member which is provided such that this conventional frame member, the damper support portion, and the wheel house are aligned in the vehicle width direction (i.e., an axial center of the frame member extending along its longitudinal direction is offset inwardly in the vehicle width direction).
In this case, however, smooth transmission of a collision load transmitted from a front portion of the frame member to a rear portion of a side sill when an obstacle collides with a rear portion of the vehicle (in a vehicle rear collision), in particular, may not be attained by simply connecting the front portion of the frame member and the rear portion of the side sill. Accordingly, there is a concern that there may occur deformation in that an overlapping amount, in the vehicle longitudinal direction, of the frame member and the side sill becomes large, that is, the frame member and the side sill together produce a Z shape in a plan view. Therefore, some countermeasures, such as increasing a plate thickness of each of the frame member, the side sill, and the like, are required. In this case, however, a new problem that the weight increases may occur.
Meanwhile, it may be considered that the front portion of the frame member and the rear portion of the side sill are not connected to each other and a frame which extends forwardly from a front end of the frame member is newly added at a position which is located on an inward side, in the vehicle width direction, of the side sill, so that the collision load is transmitted from the front portion of the frame member to the newly-added frame in the rear collision.
In this case, however, the newly-added frame is necessarily arranged at a relatively inward position in the vehicle width direction, which may cause some inferiority in securing a sufficient tank volume of a fuel tank which may be arranged on the inward side, in the vehicle width direction, of the front portion of the frame member or the newly-added frame, or in providing appropriate layout of related components of the fuel tank.